The present invention relates to a load weighting control apparatus that controls a weighting load applied to an object.
Conventional technology for performing load weighting control centers mainly on configurations employing impact absorption or mitigation, in which a spring, oil pressure, or air is used. A major aim of the conventional technology is maintenance of the shape of a controlled object and maintaining and insuring balance by mitigating an impact.
Also, as disclosed in JP 3934215B, there is a vacuum cylinder in which vacuum suction force is used as an attractive or suction load of a controlled object. FIG. 6 is a cross-sectional view that shows such a vacuum cylinder, and shows a state in which a piston has been pulled upward to form a vacuum chamber. FIG. 7 shows a state in which the piston has been closely fitted to a lower end wall.
A vacuum cylinder 100 is provided with a cylinder main body configured from a cylinder tube 8, one end wall 5 and another end wall 6 that respectively close both ends of the cylinder tube 8, a piston 3 that slides back and forth within the cylinder tube 8, and a piston rod 4 that is linked to the piston 3. The piston rod 4 is provided in a state passing through the other end wall 6, and along with back and forth sliding of the piston 3, operates back and forth. An air vent 2 where air is discharged outside of the cylinder main body is formed in the one end wall 5, a valve 19 capable of opening/closing is provided in the air vent 2, and thus the inside of the cylinder tube 8 is opened or tightly closed. In this configuration, after the piston 3 is closely fitted to the one end wall 5 and the valve 19 is put in a closed state as shown in FIG. 7, due to the pressure difference between a vacuum chamber 7 in a vacuum state formed between the piston 3 and the one end wall 5 by sliding the piston 3 in the opposite direction as that closely fitted side as shown in FIG. 6, and an atmospheric chamber 20 with an atmospheric pressure, a load occurs on the piston 3.
However, in the above technology, there is a limit to the range of effects obtained according to the aims of that technology. For example, when a new impact has been received during control, the controlled object weighting load appropriately increases according to the size of that impact, and to that extent, the amount of energy usage necessary for control increases.